In the prior art, there exists the multilayer wiring substrate for mounting a semiconductor chip. In the multilayer wiring substrate, the chip connection pads for mounting the semiconductor chip are provided on one surface, and the external connection pads for connecting external connection terminals are provided on the other surface.
In Patent Literature 1 (Japanese Laid-Open Patent Publication No. 2002-171050), it is set forth that, in the printed wiring board in which the pads for joining the connection terminals are provided on a surface of the insulating substrate, the surface of the insulating substrate including the outer peripheral parts of the connection pads is coated with the black solder resist, whereby the heat can be radiated effectively from the electronic components.
Also, in Patent Literature 2 (Japanese Laid-Open Patent Publication No. 2008-257044), it is set forth that, in the solder resist used in the printed wiring board, or the like, when the solder resist which has excellent heat resistance and a little warp is employed, such a matter is effective that the white or black solder resist that needs to increase the amount of exposure should be used together in order to enhance a resolution.
As described later, in the wiring substrate in the related art, the solder resist is formed on the outermost area of the wiring substrate such that the connection pads are exposes, and generally the solder resist exhibits the color in green series. The semiconductor chip is flip-chip connected to the connection pads of the wiring substrate by the soldering.
In the wiring substrate in the related art, such a problem exists that the solder resist is oxidized by the heating process applied when the semiconductor chip is flip-chip connected, or the like and is easily discolored into a brown color. In the case that the solder resist is discolored, not only its appearance becomes worse, but also when the alignment is performed by the image recognition in the later assembling step, the contrast of the image becomes worse, and thus sometimes the alignment becomes difficult.